Batteries are a common power source for many household and industrial applications. They need to be of a certain strength, or voltage, in order to power devices successfully. After extended use, batteries can drain to a point where the device they are powering may not work properly or at all. Many battery-operated toys, calculators, and music players have labels warning you not to mix old batteries with new batteries. The reason is that newer batteries will drain faster to make up for the lack of power in the older batteries. A great way to determine whether the battery you intend to use has enough voltage to run your device is by using a battery tester. In this project, your challenge is to build a sensor-controlled robotic device that measures the voltage of a AA battery and tells you if it is good or needs to be replaced.
In this project, you will design and build a device for testing the usability of a AA battery. Your device should be able to detect the presence of a battery, measure its voltage with a Vernier Differential Voltage Probe, and give an audio indicator of the battery status. Batteries will be inserted and removed from the device by the operator. Your device should incorporate a motor to touch the red clip on the Differential Voltage Probe to the positive terminal of the battery and the black clip to the negative terminal. On a AA battery, the positive terminal is the metal end of the battery with the bump. The negative terminal is the flat metal end. Your program should judge the strength of the battery based upon a pre-defined voltage limit. If the voltage is above the limit, the robot should give a recognizable audio indicator, such as “high” or “good.” If the voltage is below the limit, it should give a different audio indicator.
You are strongly encouraged to use the Engineering Design Method and your creative imagination when tackling this challenge. The Engineering Design Method will help you develop a successful working robot. A little planning will save you time and frustration, especially when working on more complicated projects.
Sensors and Equipment
This project features the following Vernier sensors and equipment.